A radio communication apparatus, such as a portable phone and a PHS, has recently become multifunctional so as to be able to execute; for instance, an application, such as a Bluetooth application, a W-LAN application, and a GPS application, in addition to being able to make a call or carry out E-mail communications. As a result of expansion of functionality, the radio communication apparatus is frequently equipped with an application antenna element as well as a communication antenna element. FIG. 11 is an oblique perspective view showing an external view of a radio communication apparatus having such two antenna elements. In the drawing, a communication antenna element 101 and an application antenna element 102 are arranged in an enclosure 100 while spaced apart from each other. The communication antenna element 101 is supplied with communication power, and the application antenna element 102 is supplied with application power.
In the meantime, as shown in FIG. 12, when the radio communication apparatus is placed on a metal plate 200, such as a metallic desk, an antenna gain of the radio communication apparatus drops. For this reason, an attempt is made to prevent deterioration of the antenna gain by providing the radio communication apparatus with a passive element 103. The passive element 103 is provided, as distinct from the application antenna element 102, only for enhancing an antenna gain.
An element effecting the same function as that of the passive element 103 shown in FIG. 12 is a “radiating element” described in connection with; for instance, Patent Document 1. The radiating element is connected to a ground face of a substrate provided in an apparatus main body in a thicknesswise direction of the apparatus main body (i.e., a substantially perpendicular direction achieved when the apparatus main body is placed on a desk, or the like). A high frequency current flows into a circuit board as described in connection with Patent Document 1. In a state where the communication terminal is placed on a metal plate, a high frequency current of opposite phase flows into the metal plate by a mirror image effect. For this reason, the high frequency current is canceled, whereupon radiation of the antenna is weakened, thereby deteriorating the antenna gain. However, a component perpendicular to the metal plate does not cancel each other, so that the radiating element symmetrically makes up a dipole antenna with respect to the metallic plate. Deterioration of an antenna gain is thereby prevented.    Patent Document 1: WO 2004-042947